Why can having an understanding of imagery, proportion, balance, and design you to evaluate the validity of an artwork?

Because they are helping us to estimate the artwork at the first look

Explanation:

When we are looking at some piece of art, the best way to recognize experience and effort of the artist is to understand imagery, proportion, balance, and design because it is easier for us with that knowledge to estimate certain style, period or skills that artist was trying to show to people.

For example, we have some pieces of proportion that are really poor and that can confuse the one that is watching because it will look off and the good proportion will look good because of the pleasure that the viewer can have while looking at it. Design can also help us to see what is the style of the painting and what are the used skills or what period do they belong to.

6

Ibelieve it is called classical  sculpture